EUVD-2026-39565

HMAC zero-length tag forgery in EVPDigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or otherwise truncated...

CVE-2026-6331

HMAC zero-length tag forgery in EVPDigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or otherwise truncated...

PYSEC-2018-52

A flaw was found in python-cryptography versions between =1.9.0 and 2.3. The finalizewithtag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalizewithtag an attacker could craft an invalid payload with a shortened tag e.g. 1 byte suc...